Molecular forms of rat angiotensinogen in plasma and brain: identification by isoelectric focusing and immunoblot analysis

Thomas, WG, Kerr, D and Sernia, C (1995) Molecular forms of rat angiotensinogen in plasma and brain: identification by isoelectric focusing and immunoblot analysis. Regulatory Peptides, 59 1: 31-41. doi:10.1016/0167-0115(95)00071-I


Author Thomas, WG
Kerr, D
Sernia, C
Title Molecular forms of rat angiotensinogen in plasma and brain: identification by isoelectric focusing and immunoblot analysis
Journal name Regulatory Peptides   Check publisher's open access policy
ISSN 0167-0115
Publication date 1995-09-22
Sub-type Article (original research)
DOI 10.1016/0167-0115(95)00071-I
Volume 59
Issue 1
Start page 31
End page 41
Total pages 11
Language eng
Subject 1303 Specialist Studies in Education
1308 Clinical Biochemistry
1310 Endocrinology
1314 Physiology
2804 Cellular and Molecular Neuroscience
2800 Neuroscience
Abstract Angiotensinogen (Ao) is the glycoprotein precursor of the vasoactive peptide angiotensin II. While Ao is synthesized as multiple molecular forms, the biochemical characteristics of this protein in blood and other tissues have not been defined. In this study, the charge heterogeneity of Ao in rat plasma, cerebrospinal fluid and that secreted by astrocyte and neuronal cultures was examined using analytical isoelectric focusing in combination with immunoblotting and quantitative image analysis. Normal rat male plasma Ao separated into 9 isoforms in the pI range 4.34-4.92 (1, 4.34; 2, 4.41; 3, 4.48; 4, 4.58; 5, 4.61; 6, 4.66; 7, 4.68; 8, 4.81; 9, 4.92); the percentage contribution of each to total plasma Ao was 13, 20, 23, 18, 2, 7, 10, 5, and < 1, respectively. A similar isoelectric focusing pattern was observed in female rat plasma with the exception that the relative contribution of isoform 6 was reduced to 2% of total Ao. Cerebrospinal fluid Ao displayed a more diverse charge heterogeneity than plasma Ao, focusing over a broader pI range of 4.42-5.24. Astrocytes and neurons secreted Ao isoforms in the pI range 4.44-5.29 and 4.42-4.95, respectively, with the astrocyte cultures showing additional bands towards the cathode. It was concluded that rat Ao is secreted as multiple charged forms that are regulated in a sex- and cell-specific manner. These differences between plasma and brain Ao suggest a functional diversity, a view which is supported by recent evidence linking Ao variants to hypertension.
Keyword Angiotensinogen
Isoelectric focusing
Renin-angiotensin system
Tissue-specific expression
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
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